High-efficiency treatment system for aramid fiber 1414 by-product

Abstract

The utility model discloses an aramid 1414 by-product high-efficiency treatment system, which comprises a heat exchanger, a dilute sulfuric acid storage tank, a crystallizer, a thickener and a filter which are connected in sequence, the heat exchanger is provided with a dilute sulfuric acid inlet and a dilute sulfuric acid outlet, the dilute sulfuric acid inlet is connected to a coagulating bath recovery tank, and the dilute sulfuric acid outlet is connected to the dilute sulfuric acid storage tank; the number of the crystallizers is at least two, the crystallizers are connected in series between the dilute sulfuric acid storage tank and the thickener through pipelines, and a calcium carbonate slurry inlet is formed in the crystallizer at the first stage. By adopting the combined use of the heat exchanger, the crystallizer and the thickener, the reaction time of dilute sulphuric acid and calcium carbonate can be shortened, so that the disposal capacity of dilute sulphuric acid is improved, and the productivity of aramid fibers is improved.

Description

Technical Field

[0001] The utility model is a high-efficiency treatment system for aramid 1414 by-products, specifically a process system for improving the treatment efficiency of aramid 1414 by-products in dilute sulfuric acid, and belongs to the technical field of fiber production equipment. Background Art

[0002] Poly(p-phenylene terephthalamide) fiber, also known as aramid 1414 fiber and para-aramid fiber, is an organic synthetic fiber with high strength and high modulus. It is widely used in important fields such as bulletproof, automotive hoses, and optical cables. It is an important basic material for the construction of aerospace and national defense military industries.

[0003] Currently, as the production capacity of aramid 1414 increases, the amount of dilute sulfuric acid produced as a byproduct also increases. The dilute sulfuric acid produced as a byproduct in existing aramid 1414 production is primarily produced through an acid-base neutralization reaction with calcium carbonate to form calcium sulfate. For example, Patent Publication No. CN103395816A describes a process for producing calcium sulfate dihydrate from waste acid liquor from aramid II spinning. This process involves filtering and buffering the waste acid liquor to control the sulfuric acid concentration fluctuation range. The waste acid liquor is then added to a reaction crystallization device, where the sulfuric acid reacts with calcium carbonate in a heavy calcium slurry to form a crystal. The resulting reaction crystallization slurry is then filtered and precipitated to produce calcium sulfate dihydrate. However, in the actual production of aramid 1414, the temperature of the by-product dilute sulfuric acid is usually below 5°C. When low-temperature dilute sulfuric acid undergoes acid-base neutralization reaction with calcium carbonate, the reaction time of low-temperature dilute sulfuric acid and calcium carbonate is longer than that of normal temperature (>15°C) dilute sulfuric acid and calcium carbonate. The reaction speed of low-temperature dilute acid is slower than that of normal temperature dilute acid, resulting in lower acid-base neutralization efficiency and smaller dilute sulfuric acid disposal capacity. Under the same production equipment, this seriously affects the increase in aramid production.

[0004] In order to further improve the disposal efficiency of dilute sulfuric acid and thus expand the production capacity of aramid 1414, industry insiders are constantly updating production processes, adjusting process parameters, and updating equipment to meet the demand for producing aramid 1414 fiber products with higher production requirements. Utility Model Content

[0005] The utility model aims to solve the problem of low efficiency in the treatment of dilute sulfuric acid in the existing aramid 1414 fiber production process, and proposes a high-efficiency treatment system for aramid 1414 by-products. The system adopts the combined use of a heat exchanger, a crystallizer and a thickener, which can shorten the reaction time of dilute sulfuric acid and calcium carbonate, thereby improving the treatment capacity of dilute sulfuric acid and increasing the production capacity of aramid fiber.

[0006] The utility model is achieved through the following technical solutions: a high-efficiency treatment system for aramid 1414 by-products, comprising a heat exchanger, a dilute sulfuric acid storage tank, a crystallizer, a thickener and a filter connected in sequence, wherein the heat exchanger is provided with a dilute sulfuric acid inlet and a dilute sulfuric acid outlet, the dilute sulfuric acid inlet is connected to a coagulation bath recovery tank, and the dilute sulfuric acid outlet is connected to the dilute sulfuric acid storage tank; the number of crystallizers is at least two, the crystallizers are connected in series between the dilute sulfuric acid storage tank and the thickener through pipelines, and a calcium carbonate slurry inlet is provided on the crystallizer located at the first stage.

[0007] A dilute sulfuric acid delivery pump and a dilute sulfuric acid regulating valve are provided on the pipeline between the dilute sulfuric acid storage tank and the crystallizer connected thereto, and a calcium carbonate slurry regulating valve is provided on the connecting pipeline of the calcium carbonate slurry inlet on the crystallizer. The dilute sulfuric acid regulating valve and the calcium carbonate slurry regulating valve are interlocked for control.

[0008] Calcium slurry pumps are installed on the connecting pipes between adjacent crystallizers, between the crystallizer and the thickener, and between the thickener and the filter.

[0009] A delivery pump is provided on the connecting pipeline between the coagulation bath recovery tank and the heat exchanger.

[0010] The heat exchanger is provided with a dilute sulfuric acid channel and a primary water washing recovery liquid channel for mutual heat exchange. The dilute sulfuric acid inlet and the dilute sulfuric acid outlet are located at the ends of the dilute sulfuric acid channel. The outlet of the primary water washing recovery liquid channel is connected to the coagulation bath system.

[0011] The heat exchanger is a plate heat exchanger.

[0012] The filter is a belt filter.

[0013] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0014] (1) The utility model shortens the reaction time of dilute sulfuric acid and calcium carbonate based on the combined use of a heat exchanger, a dilute sulfuric acid dilution tank, a crystallizer, a thickener and a filter, which can effectively improve the handling capacity of dilute sulfuric acid and meet the increase in the production capacity of aramid 1414 fiber.

[0015] (2) The utility model uses a heat exchanger to convert the thermal energy of the primary water washing recovery liquid in the aramid 1414 production system, so that the temperature of the dilute sulfuric acid is increased. The cooled primary water washing recovery liquid is then supplied to the coagulation bath system for use, which rationally utilizes the system thermal energy and has low energy consumption.

[0016] (3) The present invention adopts at least two crystallizers, which can allow the dilute sulfuric acid and calcium carbonate slurry to undergo a pre-reaction through the crystallizer. The unreacted calcium carbonate and dilute sulfuric acid are then transported to the next-stage crystallizer to continue the reaction and crystallization, which can improve the reaction efficiency of the dilute sulfuric acid and calcium carbonate and shorten the reaction time.

[0017] (4) In the present invention, the thickener is provided to allow the calcium sulfate obtained by the reaction to crystallize and expand again, which is beneficial for subsequent filtration to obtain the calcium sulfate product, thereby increasing the product yield and improving the handling capacity of dilute sulfuric acid. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the process of the present utility model.

[0019] Among them, 1 is heat exchanger, 2 is dilute sulfuric acid storage tank, 3 is crystallizer, 4 is thickener, 5 is filter, 6 is dilute sulfuric acid inlet, 7 is dilute sulfuric acid outlet, 8 is coagulation bath recovery tank, 9 is calcium carbonate slurry inlet, 10 is dilute sulfuric acid delivery pump, 11 is dilute sulfuric acid regulating valve, 12 is calcium carbonate slurry regulating valve, 13 is calcium slurry pump, and 14 is delivery pump. DETAILED DESCRIPTION

[0020] The present invention will be further described in detail below with reference to the embodiments, but the embodiments of the present invention are not limited thereto.

[0021] Example:

[0022] This embodiment is a high-efficiency processing system for aramid 1414 byproducts.

[0023] See also Figure 1 As shown, the system mainly consists of a heat exchanger 1, a dilute sulfuric acid storage tank 2, a crystallizer 3, a thickener 4, a filter 5 and other equipment. It can shorten the reaction time of dilute sulfuric acid and calcium carbonate, a by-product in the production process of aramid 1414 fiber, improve the disposal efficiency of dilute sulfuric acid, and meet the increase in aramid fiber production capacity.

[0024] In this embodiment, heat exchanger 1 can be a plate-type heat exchanger, each provided with a dilute sulfuric acid channel and a primary water wash recovery liquid channel for the passage of heat exchange medium. The outlet of the primary water wash recovery liquid channel is connected to the coagulation bath system. The dilute sulfuric acid channel is provided with a dilute sulfuric acid inlet 6 and a dilute sulfuric acid outlet 7, respectively. The dilute sulfuric acid inlet 6 is connected to a coagulation bath recovery tank 8. A delivery pump 14 is provided between the coagulation bath recovery tank 8 and the heat exchanger 1; the dilute sulfuric acid outlet 7 is connected to the dilute sulfuric acid storage tank 2. The coagulation bath recovery tank 8 is used to hold the dilute sulfuric acid produced in the production of aramid 1414 fibers. The delivery pump 14 transports the dilute sulfuric acid through the heat exchanger 1 to raise its temperature. The heat exchanger 1 uses the dilute sulfuric acid produced in the production of aramid 1414 fibers to cool the primary water wash recovery liquid used and supply it to the coagulation bath system. This effectively lowers the primary water wash recovery liquid to the coagulation bath temperature while raising the temperature of the dilute sulfuric acid. The heat exchanged dilute sulfuric acid is then transported to the dilute sulfuric acid storage tank 2.

[0025] In this embodiment, there are two crystallizers 3, which are connected in series between the dilute sulfuric acid storage tank 2 and the thickener 4 through a pipeline. A calcium carbonate slurry inlet 9 is provided on the first crystallizer 3, and a calcium slurry pump 13 is provided on the connecting pipeline between the two crystallizers 3. Figure 1 As shown, the dilute sulfuric acid storage tank 2 is connected to the crystallizer 3 at the first stage by a pipeline, and a dilute sulfuric acid delivery pump 10 and a dilute sulfuric acid regulating valve 11 are installed on the pipeline. At the same time, the calcium carbonate blending tank is connected to the calcium carbonate slurry inlet 9 of the crystallizer 3 at the first stage by a pipeline, and a calcium carbonate regulating valve is installed on the pipeline. By interlocking the dilute sulfuric acid regulating valve 11 and the calcium carbonate slurry regulating valve 12, the ratio of dilute sulfuric acid and calcium carbonate in the crystallizer 3 can be controlled. During use, the dilute sulfuric acid and calcium carbonate slurry are controlled to be fed into the crystallizer 3 at the first stage in a ratio of 1:1. After the dilute sulfuric acid and calcium carbonate slurry pre-react in the crystallizer 3, the unreacted dilute sulfuric acid and calcium carbonate are transported to the crystallizer 3 at the next stage through the calcium slurry pump 13 to continue the reaction and crystallization. The calcium sulfate slurry generated by the final reaction is then sent to the thickener 4.

[0026] Thickener 4 can cause the calcium sulfate slurry to crystallize and expand again. A calcium slurry pump 13 is provided on the connecting pipes between thickener 4 and the lower-stage crystallizer 3, and between thickener 4 and filter 5. During use, the calcium sulfate slurry obtained in the lower-stage crystallizer 3 is transported to thickener 4 via calcium slurry pump 13. After the calcium sulfate slurry crystallizes and expands again, it is also transported to filter 5 (e.g., a belt filter) via calcium slurry pump 13. Filter 5 is connected to a vacuum pump, and the calcium sulfate slurry is vacuum filtered to remove excess water, thereby obtaining a calcium sulfate product.

[0027] Compared with the existing direct reaction crystallization treatment method of dilute sulfuric acid and calcium carbonate, the above-mentioned treatment system of this embodiment can shorten the time for the dilute sulfuric acid to react and generate calcium sulfate in the coagulation bath recovery tank 8. At the same time, the delivery pump 14, calcium slurry pump 13, etc. are used between the various devices to transport materials, and the regulating valve is linked to realize the control of the material ratio, which can realize the continuity and automation of the treatment process and further improve the disposal efficiency of dilute sulfuric acid.

[0028] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification or equivalent change made to the above embodiment based on the technical essence of the present invention falls within the scope of protection of the present invention.

Claims

1. A high-efficiency treatment system for aramid 1414 byproducts, characterized by: The invention comprises a heat exchanger (1), a dilute sulfuric acid storage tank (2), a crystallizer (3), a thickener (4) and a filter (5) connected in sequence, wherein the heat exchanger (1) is provided with a dilute sulfuric acid inlet (6) and a dilute sulfuric acid outlet (7), the dilute sulfuric acid inlet (6) is connected to a coagulation bath recovery tank (8), and the dilute sulfuric acid outlet (7) is connected to the dilute sulfuric acid storage tank (2); the number of crystallizers (3) is at least two, and the crystallizers (3) are connected in series between the dilute sulfuric acid storage tank (2) and the thickener (4) through a pipeline, and a calcium carbonate slurry inlet (9) is provided on the first-stage crystallizer (3).

2. The high-efficiency treatment system for aramid 1414 byproduct according to claim 1, characterized in that: A dilute sulfuric acid delivery pump (10) and a dilute sulfuric acid regulating valve (11) are provided on the pipeline between the dilute sulfuric acid storage tank (2) and the crystallizer (3) connected thereto, and a calcium carbonate slurry regulating valve (12) is provided on the connecting pipeline of the calcium carbonate slurry inlet (9) on the crystallizer (3). The dilute sulfuric acid regulating valve (11) and the calcium carbonate slurry regulating valve (12) are interlockedly controlled.

3. The high-efficiency treatment system for aramid 1414 byproduct according to claim 1, characterized in that: Calcium slurry pumps (13) are provided on the connecting pipes between adjacent crystallizers (3), between the crystallizer (3) and the thickener (4), and between the thickener (4) and the filter (5).

4. The high-efficiency treatment system for aramid 1414 byproduct according to claim 1, characterized in that: A delivery pump is provided on the connecting pipe between the coagulation bath recovery tank (8) and the heat exchanger (1).

5. The high-efficiency treatment system for aramid 1414 byproduct according to claim 1, characterized in that: The heat exchanger (1) is provided with a dilute sulfuric acid channel and a primary water washing recovery liquid channel for mutual heat exchange, the dilute sulfuric acid inlet (6) and the dilute sulfuric acid outlet (7) are located at the ends of the dilute sulfuric acid channel, and the outlet of the primary water washing recovery liquid channel is connected to the coagulation bath system.

6. The high-efficiency treatment system for aramid 1414 byproduct according to claim 5, characterized in that: The heat exchanger (1) is a plate heat exchanger.

7. The high-efficiency treatment system for aramid 1414 byproduct according to claim 1, characterized in that: The filter (5) is a belt filter.

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